Currently, there are over 120 Principal Investigators at Boston University Medical campus, who utilize mice, of which a majority differ in their genetic composition or genotype. Description of their phenotype and physiology is of paramount importance to optimize the translational potential to humans. Routinely, mice are housed in temperatures, may range from 18-26 C (64-79 F). While these temperatures conform to guidelines as described in Guide for the Care and Use of Laboratory Animals, exposure to these wide temperature fluctuations are known to cause behavioral, physiologic, and morphologic changes, which negatively affect animal well-being and research performance as well as outcomes of research protocols which may compromise their translational potential. Different ambient temperatures have been shown to cause changes in food intake, body mass, organ weight, torpor, substrate utilization, thermogenesis, tumor resistance, immune response and various cardiovascular parameters. We are requesting funds to obtain an Oxymax 24 chamber system, which is contained within a highly regulated ( +/- 1C) temperature enclosure (Columbus Instruments) that would allow multiple users to conduct studies on energy expenditure, fuel utilization, spontaneous activity, sleep analysis of mice in controlled environments. Additionally, temperature range of this instrumentation can be programed from 2C - 50C allowing experimentation at either cold (4C) or thermoneutrality (30C), which are routine interventions on protocols of different users, who study the formation of brown adipose tissue or minimization of facultative thermogenesis. Such measures would be performed concurrently on up to 24 mice, allowing quantitative assessment and comparison of different metabolic parameters in various animal models which differ in age, gene expression, plasticity to different dietary/ exercise regimens and/or pharmaceutical therapies. The requested instrumentation will be used by 8 investigators funded by 12 RO1 grants and 1 PO grant.